Originally Posted By: jstutz
Im just trying to understand the advantages of blending a higher quality basestock with lower one because it still has the lower quality basestock in it. I guess if you had a 50/50 blend and ran at the limits of the lower quality one, it is better to have 50 percent of your oil oxidizing than 100 percent. Plus the added benefit of having to use less VII.
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...makes me think that you could potentially have a standard dino that is better than a syn blend.
Exactly. In theory synblend increases the stability of the base by a) decreasing the VII percentage and b) increasing the oxidative stability.
In the real world, in the best case it could be that. In the worst case it absolutely could be worse, if the unscrupulous company decides to use a cheaper II + a bottom-rung III, or simply use cheaper II + a tiny amount of III, just enough to meet "blend" definition (what is it, >3%?). Said company can definitely also make the synblend more expensive.
The truth is, as with most things, somewhere in between. Some synblends are probably just marketing gimmicks and no better than dino at all. Some synblends are a tad bit better than a dino, but totally not worth the cost. And some synblends are quite a bit better and possibly worth the cost. Throw in different companies, different regions, different facilities, batch-to-batch variability, engine variability, temperature variability, and what you end up having is the mother of all cr*pshoots.
Originally Posted By: jstutz
Seems like a 15% grp three mix in a primarily gr2+ is not much benefit.
Benefit? It would depend on the quality of the II. As tenderloin linked, you can have anywhere from avg VI 102, to VI 118 for II+, just from Chevron alone. And if you refer to
100N base stock sample analyses here a good Group II+ nearly DOUBLES the oxidative resistance of a lower-end Group II.